Golay plots

GC analysis was also carried out on a Si-glass chip using an off-chip flame ionization detector (FID). Figure 6.2 shows the Golay plots (cf. Van Deemter plots) of the n-C9 peak when both the native and oxidized Si surfaces were used. H, is lower in native Si because of the less polar stationary phase. Figure 6.2... 

Note that the C term varies directly with carrier gas velocity and the B term varies inversely. Dispersion due to the mass transfer term, C, is a function of the component/stationary phase interaction and is the critical dispersion term. There are two components, mass transfer in the mobile phase. Cm, and in the stationary phase, Cs- Figure 5.3 shows the van Deemter/Golay plots for packed and WCOT columns and the effect of film thickness. 

FIGURE 5.1 Golay plots for air, hydrogen, and helium as carrier gases using a 10-m-long, 0.25-mm-i.d. thin-film colnmn. Literature values of gas viscosity and binary diffusion coefficients for benzene at 50°C are used. A retention factor of 2.0 is assumed. 

FIGURE 5.2 Golay plots for 10-m-long, thin-film columns of various diameters using hydrogen as carrier gas. A binary diffusion coefficient of 0.4 cm /s and a retention factor of 2.0 are assumed. 

Column efficiency at high average carrier-gas velocities can be increased by operating the column at reduced outlet pressure. Gas-phase binary diffusion coefficients scale inversely with gas density and thus any reduction in pressure results in larger Dq values. This causes an increase in longitudinal diffusion and a decrease in resistance to mass transport in the gas phase. The result is an increase in opt and a decrease in the slope of the right-hand flank of the Golay plots (see Equations 5.5 and 5.8). 

The Dq values used in Equations 5.5 and 5.8 are specified for the column outlet pressure. When a vacuum pump is used to reduce the column outlet pressure, the Dq values at the outlet pressure are found as the product of the atmospheric-pressure values and the ratio of atmospheric pressure to the column outlet pressure. Figure 5.4 shows column efficiency (Golay) plots for 5-m-long, thin-fihn columns operated with hydrogen carrier gas at 50°C and assuming a Dq value of 0.4 cm /s at atmospheric pressure. Broken-line plots are for an outlet pressure of 1.0 atm, and the solid-line plots are for an outlet pressure of 0.01 atmosphere. The top pair of plots is for a 0.1-mm-i.d. column, the center pair for a 0.25-mm-i.d. column, and the bottom pair for a 0.53-mm-i.d. (megabore) column. 

FIGURE 5.4 Golay plots for atmospheric outlet pressure (dotted lines) and 0.01 atmosphere outlet pressure (solid hues) using 5.0-m-long columns with hydrogen carrier gas and i.d. values of 0.10 mm (a), 0.25 mm (b), and 0.53 mm (c). A binary diffusion coefficient of 0.4 cm /s and a retention factor of 2.0 are assumed. 

Figure 3. Plot of the loss tangent with temperature for Hytrel in the temperature range of 0 to 140 Deg. The x s represent the experimental values, while the solid line represents the results of smoothing using the Savitzky-Golay technique.

A sample plot showing the contribution of each term to determining H is shown in Fig. 14.2. An excellent basic discussion of the van Deemter and Golay equations can be found in the text by McNair and Miller [10]. 

Calculate the five point Savitsky-Golay quadratic first and second derivatives of A. Plot the graphs, and interpret them compare both first and second derivatives and discuss the appearance in terms of the number and positions of the peaks. 

A hybridization probe-pair placed over a heterozygous polymorphism is shown in Figure 37-29. The reporter probe is complementary to the normal allele. As the temperature is increased, the mismatched mutant hybrid melts first, giving the first transition, followed by the matched normal hybrid. The melting temperatures of both hybrids are easily seen in the derivative plot generated by numerical Savitzky-Golay... 

Sampling theory, 27 Savitsky-Golay coefficients, 41 Savitsky-Golay differentiation, 57 Savitsky-Golay smoothing, 38 Scatter plot, 24 Scores, factor, 74 Scree plot, 75... 

Figure 6 Influence of the Savitzky-Golay window width on the shape of the derivatives - shown are second derivatives of the absorption spectrum plotted in the upper left graph of Figure 1.

Figure 2 Chromatographic efficiency (A) and a chromatogram (B) obtained using an end-column electrochemical detector coupled to an OTLC column. (A) Experimentally measured data of the OTLC system (plotted points) is compared to the theoretical efficiency as predicted by the Golay equation (solid eurve) for a column diameter of 14 pm and diffusion coefficient of 10 cmVs. (B) Chromatogram obtained for an injection of 0.76 pg hydroquinone onto a 14 pm x 1.2 m column operated at 6 mm/s. (Adapted from Ref. 13.)...

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